What is a Relation ?
•A
mathematical definition:
–if
A, B are sets, then a relation R is a subset of A x B
•A={1,2,3}, B={a,b,c,d},
R = {(1,a), (1,c), (3,b)}
-
makes is a subset of Product x Company:
1
2
3
a
b
c
d
A=
B=
makes
Company
Product